This research plan describes the development of a chronic interface to transduce electrical signals from mammalian peripheral nerves to external prosthetics. In preliminary work, rabbit peripheral nerves have regenerated through a semiconductor substrate and re-established functional connections. An electrode system with transcutaneous leads is the main concern of this proposal. The interface consists of a semiconductor substrate which has electrical contacts in close proximity of the regenerated nerve. This proposal would continue a study of the long term interaction of nerves and nerve signals with the interface. In addition, this device will be used to investigate the long term function of nerves when severed from their end organs. A passivation system to protect electronics on the device from biological tissue and fluids will be developed. An optimum electrode structure with a multiplexing system will be designed. Electrode selection will be based on measured signals, noise and biocompatibility of various implanted devices including those now in testing. The long term goal is to develop a neuro-electric interface with sufficient resolution to establish completely functional prosthetics. The interface would be useful for amputees, quadriplegics and other handicapped individuals.